Method of making end rings for cylindrical containers

ABSTRACT

A method of forming can end rings from linear flat strip stock first establishes a plurality of flutes along one edge of the flat stock. This causes a circular shape to be formed having two free ends. The free ends are joined together and the thusly formed ring is then pressed into the finally desired channel shaped end ring. One method of forming the flutes does so in a continuous manner such that a helix is formed which must then be cut at proper intervals. An alternate method forms rings from individual pieces of flat strip stock.

"United States Patent 1191 Redd et al. 1

[ 1 METHOD OF MAKING END RINGS FOR CYLINDRICAL CONTAINERS [75] Inventors: Michael Eugene Redd; Robert Clyde Rieke, both of Longview, Wash.

[73] Assignee: Weyerhaeuser Company, Tacoma,

Wash.

[22] Filed: Apr. 18,1973 [21] Appl. N0.: 352,163

521 u.s.c1. 113/121c, 113/116 HA, 29/1573 B, 72/137, 220/67, 229/57 151 1111. c1 B2ld 51/44 [58] Field 61 Search 72/131, 137; 29/1573 A, 29/l56.6, 157.3 B; 229/57; 113/120 R, 116

BB, 116 12,121 R, 121 c, 116 1), 116 HA;

[56] References Cited UNITED STATES PATENTS 2,170,325 8/1939 Harrison 113/116 HA 1111- 3,814,041 June 4, 1974 Sturdy...., 1'13/121 R 2,532,239 1l/l950 Newlin 72/137 3,122,990 3/1964 Fried 99/369 3,146,749 9/1964 Heinle 113/121 C 3,472,417 10/1969 Fox 220/67 Primary Examiner-Richard J. Herbst 5 7 ABSTRACT A method of forming can end rings from linear flat strip stock first establishes "a plurality of flutes along one edge of the flat stock. This causes a circular shape to be formed having two free ends. The free ends are joined together and the thusly formed ring is then pressed into the finally desired channel shaped end ring. One method of forming the flutes does so in a continuous manner such that a helix is formed which must then be cut at proper intervals. An alternate method forms rings from individual pieces of flat strip stock.

7 Claims, 15 Drawing Figures PATENTEDJUN 41914 SHEET 3 BF 3 METHOD OF MAKING END RINGS roa CYLINDRICAL CONTAINERS BACKGROUND OF THE INVENTION This invention relates generally to a method for making circular rings from linear flat stock and more-particularly to a method for making circular end rings for cylindrical containers from flat stock. I

In the formation of cylindrical containers, such as quart oil cans, beverage cans, and the like, it is customary to utilize a circumferential ring'about the top and- /or bottom of the container to provide a suitable joining means for the respective closures to the cylindrical por- 7 tion of the container. Sometimes these rings are integral with the closure means while at other times they are separate circumferential rings with a closure then being positioned across the ring opening and affixed thereto. a

One example of a separate circumferential ring fora container may be seen by referring to US. Pat. No. I

3 ,l22.990 issued to L. Fried. Another exanipie in ay be seen by referring to US. Pat. No. 3,472,417 issued to J. F. Fox. Both of the circumferential rings disclosed in these prior art patents are formed by stamping from a flat solid piece of suitable material and then press forming them into the desired cross-sectional configuration for fitting onto the end of the container. This method of forming I circumferential end rings is extremely wasteful ofmaterial'and is a relatively high cost production method. One obvious method of alleviating this tially starting with pieces of flat strip stock. Of course,

in view of the high numbers of circumferential rings that are required, the process must offer high production rates. I

Accordingly, from the foregoing, one object of the present invention is.to offer acircumferential ring forming process that results in substantially less waste.

'Another'object of the invention is to offer a circumferential ring forming process that utilizes generally linear flat stock, converting it to the circumferential rings.

Yet afurther object is to offer a process for producing the circumferential rings that results in high production rates. A

These and other objects of the present invention will become apparent upon reading the following specification in conjunction with the attached drawing.

SUMMARY OF THE INVENTION The present invention is a method of forming a circumferential container end ring from a generally linear blank and is comprised of the steps ,of forming a plural ity of flutes along one side of the blank, thereby causing the blank to assume a curvilinear ring shape. Two op-,

posing ends of the now curvilinear blank material are joined together through a suitable bonding step, thus forming a generally circumferential ring having flutes about the inside circumference. Finally, the circumferential ring is pressed vertically toform the desired cross-section for the ultimately desired circumferential container ring.

DEscRIPrIoNoF THE DRAWING In the accompanying drawing, in which the same reference numbers designate the same parts in all of the views:

FIG. 1 is an isometric view of an upstandingcylindri-- cal container showing the top and bottornclosures in place;

FIG. 2 is an isometric view showing a portion of the generally linear flat stock from which the circumferential ring is made;

FIG. 3 is a cross-sectional view taken through the stock material showing its thin flat cross-section;

FIG. 4 is an isometric view showing a pair ofmeshed toothed rollers establishing flutes along an edge of the stock material;

FIG. Sis a more detailed from view showing the meshed toothed rollers with the stock material moving therethrough; i e

FIG. 6 is an isometric view showing a single ring that is partially formed but prior to bonding opposing ends together;

FIG. 7 is a cross-section through the partiallyformed.

ring of FIG. 6;

FIG. 8 is an isometric view showing the circumferential ring after the ends have been joined together and partial vertical pressing has taken place;

FIG. 9 is a cross-sectional view through the circumferential ring of FIG. 8; I

FIG. 10 is an isometric view showing the circumferential ring in its final shape with the container end closure affixed to the circumferential ring;

FIG. III is a partial cross-sectional view taken through the circumferential ring prior to'being joined to the cylindrical body portion;

FIG. 12 is a partial cross-sectional view taken through the finally assembled container at the circumferential ring portion showing the attaching method for the container parts; I

F IG.I3 is a top view showing an alternate fluted ring forming apparatus;

FIG. I4 is a partial cross-sectional view through the forming heads of FIG. 13;

FIG. 15 is a similar partial cross-sectional view through a different portion of the forming heads.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1 a generally cylindrical composite container is depicted at 10 and is comprised of a cylindrical body portion 12, a top end closure portion 14, and a circumferential endring 16. At the bottom of cylindrical container 10 is a bottom end closure portion (not shown) and a bottom circumferential end ring 18. It will be recognized that it is the circumferential end rings I6, 18 that ofi'er a' certain amount of strength andv rigidity to the overall cylindrical container l0 as well as providing joinder means for joiningthe body portion 12 j to the two end closure portions.

With most presently available cylindrical containers such as paperboard oil cans, metal beverage cans, and the like, the circumferential end rings are formed from a suitable metal, such as tin plate, aluminum, or steel. The composition of the cylindrical body portion 12 normally depends upon economics and the type of product within the container. Similarly, the top and bottom end closures can be comprised of any compatible material for forming the container. In the present cylindrical container a separate end closure portion is adapted to be bonded to the circumferential end rings whereby a suitable composite container for the particular product is formed.

In accordance with the present process, the blank material from which the final circumferential end ring 16 is formed consists of the generally linear thin flat strip stock 20 as depicted in FIG. 2. The stripstock 20 can be of any suitable material as previously mentioned, but must be comprised of relatively workable material that can be easily shaped. Suitable materials would be aluminum or mild steel strip stock. The crosssectional view shown in FIG. 3 of strip stock 20 depicts the relative thinness of the material as compared to its width. The actual width of strip stock 20 depends to a degree upon the desired dimensions of the finished circumferential end ring 16 and this will become more apparent later, but suffice to say for exemplary purposes that if the circumferential end ring 16 is for a standard quart size oil can, the width of strip stock 20 will be on the order of one-half inch while its length can be continuous.

Turning now to FIGS. 4 and 5, it will be seen that a pair of powered toothed rolls 22, 24 operate to convert the linear strip stock 20 into a continuous helical pattern. The powered toothed rolls 22, 24 are driven by any suitable means (not shown) at a uniform speed of rotation. The directional arrows depicted on the faces of the powered rolls 22, 24 indicate that at the entrance nip to the combined rolls 22, 24 a piece of strip material passing therethrough will be continuously conveyed. The toothed rolls 22, 24 can have a thickness dimension that is slightly wider than the width of the strip stock 20.. The toothed rolls 22, 24 are designed such that their working faces 26 are approximately the same dimension the width'dimension of strip stock 20. Over approximately half of the working faces 26 are the respective teeth 28 cooperating together at the nip so as to mesh properly. Over the other half of each working face 26 is a generally flat area 30 which accommodates the thickness of the flat strip stock 20. Flat strip stock 20 is fed into the nip of the toothed rolls 22, 24 through suitable guide means, not shown, such that the strip stock is properly located in regard to the faces of the toothed rolls 22, 24, thereby causing approximately half of the width of strip stock 20 to be pressed into a fluted shape by'the action of the meshing teeth 28. At, the outfeed. side of the toothed rolls 22, 24 are suitable guide means such as edge holding rolls 32, 33. Edge holding rolls 32, 33 operate to generally constrain and guide the strip stock to the shape being formed. 7

The plurality of spaced teeth 28 about the circumference of the toothedrolls 22, 24 are designed to form uniform flutes 34 along one edge of the strip stock 20 that is fed through the powered rolls. The flutes 34 are pressed into shape by the tooth design and effectively act to lessen the length along one edge of the strip stock thereby causing the strip material to become curvilinear in its own plane and to form a helical shape.

The tooth shape is derived from an ideal tooth in which the length 4A+2B/CP is equal to the ratio of the outer and inner diameters of the circumferential end ring 16 to be formed; where A is the tooth height taken from the pitch circle, B is the tooth width at the top, and CP'is the distance spanning a tooth and a space. The actual teeth on the powered rolls 22, 24 have the shape of the ideal teeth but with all dimensions reduced by one-half the thickness of the flat strip stock 20. The tooth dimensions may be seen by referring to FIG. 5. Teeth 28 are cut on a diagonal across their thickness with the diagonal running from the addendum circle of the teeth 28 to the pitch circle on the other side of the tooth thickness. The tooth spaces are cut on another diagonal which runs from the root circle on the toothed roll to the pitch circle on the opposite side. By so forming the teeth 28 on the powered rolls 2 2, 24 and causing them to mesh at the nip, a continuous fluted helical ring will be formed, one turn of which is depicted at 38 in FIG. 6. It should be noted that the flutes of one turn of the continuous helix engage those of the adjacent turns above and below so that anesting structure is formed. Of course, it will also be appreciated that individual presized strips of flat stock 20 could be passed through the powered toothed rolls 22, 24 allowing each blank to be formed separately rather than in a continuous manner. I

If the strip stock is formed intoa helical ring, it will be necessary to sever individual circular rings from the helix. When this is done, the ring'blank will be as depicted in FIG. 6 at 36 having two free ends 38, 40. The cross-section through the ring blank 36 having the flutes 34 about its inside circumference is shown in FIG. 7. In order to form an integral ring blank, it is necessary to join the free ends 38, 40 together prior to further processing according to the invention. The joining step may be accomplished through any suitable means such as a lap or butt welding machine. An appropriate weld is indicated at 4].

The first pressing step takes the joined ring blank 36 and through a suitable set of dies (not shown) forms the general ring shape 42 as depicted in FIG. 8 with its cross-section depicted in FIG. 9. A circumferential channel section 44 is formed about the outer circumference. Through additional pressurethe ring blank is formed into the final cross-sectional shape as depicted at 46 in FIGS. 10 and 11 where the circumferential lip portion 48 is fonned into a generally flat member for the attachment thereto of the end closure portion 14. Thus, it will be recognized that the fluted edge of the circumferential ring is generally flattened out by the pressing step. The stress that results from flattening the flutes 34 is relieved by a combination of partial overlapping of the flattened flutes and by the formation of the curvilinear channel section 44 about the outer circumference of the ring. Any rough edges that have been formed on the ring 46 may be removed by a suitable machining or buffing step.The end closure 14 is then affixed to the circumferential lip portion 48 either on its top surface or, as depicted in FIG. 11, on its bottom surface. L I

At this point, the composite end closure generally depicted at 50 in FIG. 11 is very similar to those available in the prior art for closing off one end of a cylindrical body 12, After the product has been placed within the container the composite end closure 50 is positioned over the end of the body 12 with the circumferential channel section 44 surrounding the circumferential edge. Any suitable end seaming apparatus that is commercially available can be used to form a tight circumferential jointbetween the body portion 12 of the container and the channel section 44 of the end closure 50. This circumferential seam is generally depicted at 52 in FIG. 12 and operates to effectively seal the contained product within the cylindrical container 10.

Those skilled in the art will recognize that other ap- "paratus for forming the fluted rings could be used. A second method of forming the flutes 34 about the interior circumference of the ring blank employs a conventional bending apparatus utilizing a pair of forming heads depicted in FIGS. 13-15. The stationary forming head is depicted at 54 while the rotary forming head is depicted at 56. A circumferentially extending slot 58 is formed within'the stationary and rotary forming heads 54, 56 with the portion of the slot in the stationary forming head 54 being slightly thicker than the cooperating portion of the slot in the rotary forming head 56. The width of slot 58 is approximately equal to the width of the metal strip that will be formed into the fluted circumferential ring. One end of a piece of flat strip stock is placed in the slot formed by the stationary and rotary forming heads 54, 56 with theend held in place by a set screw 60 or other suitable holding means. The rotary forming head 56 is then moved around the stationary head 54 and a ring of the proper dimensions is formed with the resulting fluting 34 occurring in the thicker portion of the slot 58. Upon completing the circumferential travel by the rotary forming head 56, the set screw 60 is loosened and the circumferentially formed fluted ring is removed The two free ends can then be joined together and the ring pressed according to the previously described pressing step. In utilizing the forming heads 54, 56 it will be appreciated that a pre-sized piece of strip stock 20 must necessarily be utilized and that a continuous helical strip will not be produced.

While a detailed example of the principal embodiment of the present invention has been described together with an alternate embodiment, it will be understood that other modifications will occur to those skilled in the art and all such modifications are intended to be included within the scope of the appended claims.

What we claim is:

l. A method of forming a containerend ring from generally linear-flat strip stock comprising the steps of:

forming a plurality of flutes along one edge of the strip stock material such that the linear stock is caused to generally assume a circular shape with the plurality of flutes being about the inside circumference,

joining together two opposing ends of the generally circular stock, and j pressing the circular stock so as to form the desired cross sectional shape for the container end ring.

2. The method as in claim 1 wherein the strip stock is continuously fluted along one edge thereof and allowed to form into a helix shape, and

where individual circular pieces of stock are severed from the helix prior to the joining step.

3. The method as in claim 2 wherein the flutes are sized so that corresponding flutes on adjacent turns of the helix will form a nesting structure.

4. The method as in claim 1 wherein the flute forming step is carried out by passing the strip stock through a pair of meshing gears such that flutes are formed along one edge thereof by the deformation of the strip stock between the meshing gears.

5. The method as in claim 1 wherein the opposed ends are joined together by a lap weld.

6. The method as in claim 1 wherein the opposed Y ends are joined together by a butt weld.

7. The method as in claim 1 wherein the opposed ends are joined together by adhesive bonding. 

1. A method of forming a container end ring from generally linear flat strip stock comprising the steps of: forming a plurality of flutes along one edge of the strip stock material such that the linear stock is caused to generally assume a circular shape with the plurality of flutes being about the inside circumference, joining together two opposing ends of the generally circular stock, and pressing the circular stock so as to form the desired cross sectional shape for the container end ring.
 2. The method as in claim 1 wherein the strip stock is continuously fluted along one edge thereof and allowed to form into a helix shape, and where individual circular pieces of stock are severed from the helix prior to the joining step.
 3. The method as in claim 2 wherein the flutes are sized so that corresponding flutes on adjacent turns of the helix will form a nesting structure.
 4. The method as in claim 1 wherein the flute forming step is carried out by passing the strip stock through a pair of meshing gears such that flutes are formed along one edge thereof by the deformation of the strip stock between the meshing gears.
 5. The method as in claim 1 wherein the opposed ends are joined together by a lap weld.
 6. The method as in claim 1 wherein the opposed ends are joined together by a butt weld.
 7. The method as in claim 1 wherein the opposed ends are joined together by adhesive bonding. 